Several studies of American men and women find that if you ask people to identify their favorite color, women tend to select colors closer to red, and men on average tend to select colors around blue. The reason behind this difference is up in the air, but there are several theories. A recent academic paper proposes a new theory to add to the list, the ecological theory:

The authors here propose that humans prefer colors like blues and greens because those colors and ecologically healthy (blue skies, clean water, healthy vegetation), and do not prefer colors like brown because it's associated with stuff that is ecologically unhealthy (like crap and things that are rotting).

Then they went about testing the theory by correlating color preference with objects that were judged favorable or unfavorable by the test subjects. Although the ecological theory incorporates parts of several other color theories, the data seems to support this idea more than previous theories. Link

I've heard that the gene responsible for seeing red is only found on the X chromosome. So maybe females having two Xs makes them more alert to red so maybe it looks better to them than to men who only have one X?